Cut the ham and the cheese into 20 to 23 very thin slices each, with a minimum measurement of 9 1/2 by 3 1/2 inches. It is better to have slightly larger slices that can be trimmed to fit the terrine exactly than to have pieces that are too small.Line a 9 1/2 by 3 1/2 x 3 1/2 inch terrine generously with plastic wrap, leaving enough overhang to cover the top of the terrine when it is filled.

Starting with a layer of cheese, alternate layers of ham and cheese until the mold is completely filled, approximately twenty layers of each. Cover the top with the overlapping plastic wrap and press down firmly. Refrigerate overnight.